Influence of Climatic Factors on the Interannual Changes of Gonadosomatic Index of the Red Mullet Mullus barbatus ponticus in the Coastal Crimean Waters

Abstract

The analysis of the influence of climatic factors on the interannual changes of the gonadosomatic index (GSI) of the red mullet Mullus barbatus ponticus, which inhabits the coastal waters of Crimea, was carried out. The dependence of the development of the reproductive system of the red mullet, determined by the gonadosomatic index, on temperature was revealed. It was found that the correlation coefficient between changes in the average temperature during the spawning and the GSI index is r = 0.98 for females and r = 0.97 for males. The maximum monthly average GSI values were observed in females and males of the M. barbatus ponticus, accordingly, in June, 4.29 and 3.76% and in July – 4.83 and 4.17%. An analysis of the size composition of the fish showed that the females are larger than males. For females, the predominant size group is 10.0–11.0 cm, and for males 9.0–10.0 cm. It was found that the red mullet, living in the coastal waters of the Crimea, has a slight positive allometric growth. A comparison in the developmental features of the red mullet that lives in different regions of the Black Sea-Mediterranean basin was made and the differences in the change in the GSI and other parameters are analyzed.